Molecular basis for ubiquitin ligase CRL2FEM1C-mediated recognition of C-degron

Nat Chem Biol. 2021 Mar;17(3):263-271. doi: 10.1038/s41589-020-00703-4. Epub 2021 Jan 4.

Abstract

Proteome integrity depends on the ubiquitin-proteasome system to degrade unwanted or abnormal proteins. In addition to the N-degrons, C-terminal residues of proteins can also serve as degradation signals (C-degrons) that are recognized by specific cullin-RING ubiquitin ligases (CRLs) for proteasomal degradation. FEM1C is a CRL2 substrate receptor that targets the C-terminal arginine degron (Arg/C-degron), but the molecular mechanism of substrate recognition remains largely elusive. Here, we present crystal structures of FEM1C in complex with Arg/C-degron and show that FEM1C utilizes a semi-open binding pocket to capture the C-terminal arginine and that the extreme C-terminal arginine is the major structural determinant in recognition by FEM1C. Together with biochemical and mutagenesis studies, we provide a framework for understanding molecular recognition of the Arg/C-degron by the FEM family of proteins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Arginine / chemistry*
  • Arginine / metabolism
  • Binding Sites
  • Carrier Proteins / chemistry*
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism
  • Cell Cycle Proteins / chemistry*
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism
  • Cloning, Molecular
  • Crystallography, X-Ray
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Gene Expression
  • Genetic Vectors / chemistry
  • Genetic Vectors / metabolism
  • HEK293 Cells
  • Humans
  • Models, Molecular
  • Proteasome Endopeptidase Complex / metabolism*
  • Protein Binding
  • Protein Conformation, alpha-Helical
  • Protein Conformation, beta-Strand
  • Protein Interaction Domains and Motifs
  • Proteolysis
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Substrate Specificity
  • Ubiquitin-Protein Ligase Complexes / chemistry*
  • Ubiquitin-Protein Ligase Complexes / genetics
  • Ubiquitin-Protein Ligase Complexes / metabolism

Substances

  • Carrier Proteins
  • Cell Cycle Proteins
  • FEM1A protein, human
  • FEM1B protein, human
  • Recombinant Proteins
  • Arginine
  • Fem1c protein, human
  • Ubiquitin-Protein Ligase Complexes
  • Proteasome Endopeptidase Complex